[Prolonged course of an idiopathic hypereosinophilic syndrome with transition to eosinophilic gastroenteritis].

Idiopathic hypereosinophilic syndrome (IHES) is a multi-system disorder of unknown origin with eosinophilic infiltration of bone marrow and various organs, including the gastrointestinal tract. Involvement of the heart has a poor prognosis. The etiology of eosinophilic gastroenteritis (EGE) also is unclear. In this disease there is exclusive involvement of the gastrointestinal tract (including liver/bile ducts) and prognosis usually is good. Transition from one disease to the other has not yet been described. We report the 20 years' history of a male patient with an initial IHES without gastrointestinal symptoms and transition to a clinically pure EGE with resolution of any other involvement. At the age of 45 years the patient developed IHES with fever and constitutional symptoms. Fluctuating eosinophilia and symptoms necessitated continuous steroid therapy. After a 10 years' disease course watery diarrhea and malabsorption syndrome became more and more prominent. On the other hand, bone marrow eosinophilia regressed completely and blood eosinophilia partially. Biopsies showed a severe EGE of the mucosal type with involvement of the whole gastrointestinal tract. Besides the prominent eosinophilia there was a dense infiltration of the intestinal mucosa with T-lymphocytes invading the epithelium. We postulate that the destructive eosinophilic/lymphocytic inflammation is caused by a pathologic proliferation of T-lymphocytes with liberation of type 2 helper cell cytokines and consecutive stimulation of eosinophils.